A bear cub died at the weekend after its unexpected birth to a bear rescued with 18 others from an illegal bile farm in Vietnam, according to an animal welfare group.

The week-old moon bear cub, named ââ‚¬Å“Tigerââ‚¬ for the new Lunar Year, died Sunday morning despite attempts to treat it at the Moon Bear Rescue Centre near Hanoi, said Hong Kong-based Animals Asia Foundation, which runs the facility.

Tigerââ‚¬â„¢s mother is one of 19 bears rescued in January from 40-foot (12-meter) cargo containers in Binh Duong province near southern Ho Chi Minh City.

ââ‚¬Å“Our veterinary team was taken by surprise by the birth, as Vietnamese farms donââ‚¬â„¢t breed,ââ‚¬ an Animals Asia statement said.

The birth suggested that Tigerââ‚¬â„¢s mother was probably taken from the wild, against Vietnamese law, the group said.

Another rescued bear had to be euthanized after its internal organs were found to be ââ‚¬Å“rotting away,ââ‚¬ it said.

Bear bile, which is prescribed for a variety of ailments in traditional Chinese medicine, is extracted with needles in a process which activists say endangers the bears.

Bile farming has been illegal in Vietnam for years but farmers were allowed to keep the bears they already had, and in 2005 thousands were given microchips in an effort to monitor the population.

Asiatic black bears, also known as moon bears, are under threat of extinction, Animals Asia says.